1) Field of the Invention
This invention relates to apparatus for measuring volumes of material for filling cans or other containers. Most specifically, this invention relates to measuring apparatus for measuring volumes of two materials, such as semi-solid and liquid materials, for mixing together to fill containers.
2) Prior Art
The canning of semi-liquid, pasty or heterogeneous products such as jam containing lumps of fruit, animal foods with large lumps of meat, or foods for human consumption with lumps of meat or vegetables raises problems as to the control of quantity. Some of the machines known in the prior art utilize a plurality of measuring chambers mounted on a rotary support, each of said chambers including a cylinder housing a piston to receive and then discharge product. The chambers are generally arranged vertically around a circumference of the rotary support. In this configuration, an upward stroke of the piston sucks product from a tank through a supply conduit into the cylinder, with the tank generally being located in a central area of the rotary support. A downward stroke of the piston delivers the product from the cylinder into a delivery nozzle which includes a second piston to force the product therefrom into a can. A valve, located in the chamber, selectively controls the opening or closing of passages between the chamber and the tank and delivery nozzle. See, for example, U.S. Pat. No. 4,466,557.
Accurate measurement of the quantity of product delivered by the apparatus is dependent upon a great number of factors. In the past, canning of a product which comprises a liquid and a solid phase has been accomplished generally in one of two ways. A first way has been to use two separate pieces of equipment for filling a can with product. In particular, a first piece of equipment is used to fill the can partially with the more solid, viscous product, and then a second machine adds the liquid product thereto before the can is sealed. This method of canning has proved to be less than satisfactory in that two pieces of equipment or machines are required to complete a single dose for each can.
A second prior art approach involves mixing the solid viscous product with the liquid product in the tank of a single apparatus and then discharging the mixture into cans. This method has also proven to be less than satisfactory in that the more solid parts of the product tend to settle to the bottom of the tank so that the first cans filled tend to have more solid product packed therein, while the cans filled later in the process tend to contain more liquid.